1. Field of the Invention
The present invention relates to an automatic pneumatic pump for forcibly introducing sludge-laden waste liguid and more particularly, to an automatically operated pneumatic pump system for automatically cleaning a fluid level sensing unit, improving pumping capacity, and recycling discharged and compressed air.
2. Description of the Prior Art
Various types of automatic pneumatic pumps are known in the art. In typical waste water disposal systems, waste water is pumped up and forcibly fed to a filter unit where the sludge in the waste water is filtered off. In order to pump up the sludge-laden waste water, the typical waste water disposal systems are provided with pumps. In the operation of the above systems, the viscous sludge in waste water may stick to the filter unit and thereby cause an operational problem in the filter unit. In this regard the sludge-laden waste water in the above systems has been pumped up by an impeller, piston or vane type pump to be highly pressurized while being fed to the filter unit.
However, the waste water under pressure applies high pressure to the filter unit thus causing damage in the filter unit. In addition, the pump may be overloaded during such a high pressure pumping operation, so the pump regrettably generates operational noises. Another problem of the above pump resides in that the lubrication oil supplied to the drive part of the pump may leak from the pump and go into the waste water.
Accordingly, in order to solve the above problem of such a conventional pneumatic pump the present inventor developed an improvement in such automatic pneumatic pump as disclosed in U.S. Pat. No. 5,749,711 entitled an automatic pneumatic pump including a tank with an inlet and an outlet for forcibly introducing sludge-laden waste liquid such as waste water or industrial wastes into a tank and in turn supplying pressurized air into the tank at a time the tank has been filled with a predetermined amount of liquid thereby forcibly discharging the liquid outside the tank while filtering off the sludge.
However, such a the above pentented pneumatic pump suffers from a numbers of problems. For example since compressed air functions like a piston in the process of pumping fluid, pumped fluid is dispersed to the inside wall of a fluid tank and a fluid level sensing unit. As a result, sludge in the fluid adheres to the fluid level sensing unit, thereby causing a short circuit of the pneumatic pump. The short circuit of the pneumatic pump leads to failure in performing a desired proper operation. In order to eliminate this problem, the fluid level sensing unit of the pneumatic pump is constructed to be disassembled from the pump system, thereby allowing the fluid level sensing unit to be cleaned. Also, according to the pneumatic pump, since the fluid level sensing unit of the pneumatic pump system needs bolts, nuts, sealing members, washers, etc. for the disassembling, the construction of the pump is complex. Additionally, since regular clean up of the fluid level sensing unit is required, for example, 1-2 times a week, maintenance of the pump system is troublesome.
The pneumatic pump fails to operate sometimes. In such a case, when an auxiliary pump does not exist in the system, abrupt breakdowns of the pump cannot be easily dealt with.
When the pressure of the fluid tank is down, compressed air of high pressure is discharged through a solenoid valve, so that a muffler may freeze and thus be damaged due to the fall of temperature and working environment conditions may be diminished due to loud noise. Energy efficiency is low because compressed air is not recycled, but discharged to the surroundings. Additionally, since only air in an air storage tank connected to an air compressor is used to pump the fluid, an operating period of time of the air compressor may be extended, so that a great amount of electric power is consumed to operate the air compressor.